Method for producing perforated zipper for transverse direction zipper applicator

ABSTRACT

The zippers include flanges with fully or partially formed apertures or notches to allow drive rolls to positively engage and feed the zippers. Alternatively, a T-shaped guide rail can be formed on at least one flange to allow drive rolls to engage the zipper. These aspects are particularly adaptable to feeding a zipper or zipper segment to a transverse direction zipper applicator.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for producing perforatedzipper for positive and improved feeding and tracking of the zipperthrough a transverse direction zipper applicator, particularly in theart of producing reclosable packaging.

2. Description of the Prior Art

In the prior art of reclosable packaging and the methods of manufacturethereof, including form fill and seal (FFS) and related methods, it iswell-known to provide and apply the reclosable zipper in a directionwhich is transverse to the direction of movement of the film (i.e., themachine direction). While these methods are well-developed and suitablefor their intended purposes, further improvements are sought in thereliability of the tracking and placement of the zipper into the finalposition where it is sealed to the film, particularly when productionrates and speeds are increased.

In particular, nip roll systems typically include one or more sets ofsmooth or patterned rolls. However, these systems may have difficulty inconsistently pushing a soft zipper to the final desired position priorto sealing to the film. Similarly, due to the asymmetrical nature ofsome zipper profiles, zippers that travel through the nips may becomeskewed and lose their tracking. Similarly, the zipper may need to besupported between or after a set of nips. This is typically done withrollers, which may further contribute to the skewed tracking of thezipper.

Similarly, grip and pull drive systems use a chain drive or a servodriven clamp system to place the zippers. While these systems arewell-developed and suitable for their intended purposes, the zipper mayhave to be released and recaptured from the drive system in order toperform necessary options such as end crushing or cutting. This maybecome less reliable at higher production rates. Similarly, if a zippersegment that is ready to be sealed to the film is gripped by a clamp,the clamping assembly may obstruct the zipper-to-film sealing process.

OBJECTS AND SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a methodfor the transverse placement of zippers on a moving film, particularlyin the production of reclosable packages wherein the reliability of thetracking and placement of the zipper are improved, thereby leading tothe possibility of higher production rates.

This and other objects are attained by providing a zipper withperforated or punched flanges that will allow the feeding apparatus tofeed and drive the zipper positively to a transverse direction (TD)zipper application device, which places the zipper onto a filmperpendicular to the direction of film travel.

Alternatively, a textured surface is provided on the portion of thezipper flanges that face the driving rollers in the transverse directiondrive train. The texturing allows the zipper drive rollers or belts topositively engage and move the zipper forward. The texturing can berough surface which is engaged by gnurled drive rolls, or can be a shapeextruded into the zipper flange that allows the drive rollers or beltsto grab the zipper.

DESCRIPTION OF THE DRAWINGS

Further objects and advantages of the invention will become apparentfrom the following description and claims, and from the accompanyingdrawings, wherein:

FIG. 1 is a perspective view of a double-flanged zipper profile for areclosable package, with a first flange illustrating a first alternativeof punched apertures and the second flange illustrating a secondalternative of perforations.

FIG. 2 is a perspective view of a zipper formed from a double-flangedzipper profile of FIG. 1, and a single-flanged zipper profile.

FIG. 3 is a perspective view of a roller device punching apertures,perforations or similar cuts into the flanges of a double-flanged zipperprofile for a reclosable package.

FIG. 4 is a perspective view of a double-flanged zipper profile for areclosable package being driven by a toothed drive wheel whichpositively engages the apertures, perforations or similar cuts in theflanges of the zipper.

FIG. 5 is a plan view of two toothed drive wheels, illustrating theresulting positive control of zipper tension and steering.

FIG. 6 is a perspective view of a zipper being driven by rollers whichengage a rail extruded into the zipper.

FIG. 7 is a cross-sectional view along plane 7-7 of FIG. 6.

FIG. 8 is a perspective view of a zipper with driving notches extrudedor otherwise into the flanges.

FIG. 9 is a cross-sectional view of the zipper of FIG. 8 being driven bya pair of drive wheels, one with a complementary texture to the extrudeddriving notches of FIG. 8.

FIG. 10 is a schematic of a first method for forming the reclosablezipper.

FIG. 11 is a schematic of a second method for forming the reclosablezipper.

FIG. 12 is a schematic of a third method for forming the reclosablezipper.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings in detail wherein like numerals indicatelike elements throughout the several views, one sees that FIG. 1illustrates double-flanged zipper profile 12 as is used for a reclosablepackage (not shown) formed from walls of polymeric or similar material.Double-flanged zipper profile 12 is typically paired with asingle-flanged zipper profile to form a reclosable zipper 10 (see FIG.2). Double-flanged zipper profile 12 includes interlocking element 16with first flange 20 and second flange 22 extending therefrom. First andsecond flanges 20, 22 may be formed from a single piece of polymericmaterial or separate pieces of polymeric material.

In FIG. 1, the first flange 20 illustrates a first aspect of the presentinvention, wherein apertures 24 are punched or otherwise formed so as topass completely through first flange 20 so that material is removed, orat least absent from, the aperture or channel 24. The second flange 22illustrates a second aspect of the present invention wherein a C-shapedor similar cut or incision is formed in second flange 22 whereby nosignificant material is removed from second flange 22, but a flap-likestructure is formed (referred to as “perforated” herein) whereby gearsand similar structures can pass through the resulting partially formedaperture 26.

While first and second aspects of the present invention are illustratedon respective first and second flanges 20, 22, it is envisioned thatfirst and second flanges 20, 22 of zipper profile 12 will typically havesubstantially identical structures.

FIG. 2 illustrates the double-flanged zipper profile 12 of FIG. 1,joined with a single-flanged zipper profile 14, to form zipper 10.Single-flanged zipper profile 14 includes second interlocking element 18and flange 19. Second interlocking element 18 is configured and arrangedto be releasable attachable or reclosable with first interlockingelement 16. Flange 19 is illustrated with apertures 24 but may likewisebe formed with partially formed apertures 26 as described above.

Flanges 19, 20, 22 provide locations for attachment to the polymericwalls of the reclosable package (not shown).

FIG. 3 illustrates how rotary punch 100 with two sets of laterallyadjacent protrusions 102, 104 will form apertures 24 or 26 on a movinglength of double-flanged zipper profile 12. Protrusions 102, 104 may beformed as a punch to remove significant material thereby forming anaperture or channel 24 or may be formed as a C-shaped blade therebyforming an incision and the flap-like structure of the partially formedaperture 26 as described above.

FIG. 4 illustrates how drive roll 200 with radially extending spike-likeprotrusions 202 to extend through apertures 24 (or likewise, partiallyformed apertures 26 which are defined as perforated as described above)thereby positively engaging double-flanged zipper profile 12,particularly for feeding to a transverse direction zipper applicator(not shown). Drive roll 200 can have one row of radially extendingspike-like protrusions or two rows.

FIG. 5 illustrates that two drive rolls 200, 200′, particularly if therotation is monitored and controlled, such as through a servo mechanism,can closely control the tension of zipper 10 therebetween.

FIGS. 6 and 7 illustrate zipper profile 30 with male interlockingelement 32 and flange 34 extending therefrom (typically provided with acorresponding zipper profile with complementary female interlockingelement). Flange 34 further includes drive rail 36, comprising stem 38(extending perpendicularly from flange 34) and head 40 (parallel to andseparated from flange 34) thereby forming a T-shaped cross section,extending therefrom. Drive rail 36 is typically integrally extruded withzipper profile 30. Drive rail 36 is engaged by drive rolls 210, 212(also see the cross-sectional view of FIG. 7) thereby permitting driverolls 210, 212 to positively engage and feed the zipper profile 30.

FIGS. 8 and 9 illustrate zipper profile 30 with male interlockingelement 32 and row of notches or indentations 44. Notches 44, which maybe formed by extrusion, cutting, or similar processes, are parallel toeach other and transversely oriented with respect to a length of thezipper 10. This permits drive roll 214, which includes a gnurled surfacecomplementary in shape to the row of notches or indentations 44, topositively engage and feed the zipper profile 30. Typically, a smoothdrive roll 216, with a cylindrical cross section, opposes drive roll214.

FIGS. 10-12 illustrate three possible non-limiting examples ofmanufacturing methods for zipper 10. However, those skilled in the artwill recognize a broad range of equivalents after review of thisdisclosure.

FIG. 10 illustrates a first method for manufacturing the zipper 10 asdescribed above. The zipper 10 is extruded at extrusion station 400 soas to form separate first and second profiles 12, 14. Rotary punch 100forms the apertures 24 or 26 in the flanges 19, 20, 22 as describedabove. First and second profiles 12, 14 are joined by interlocking therespective interlocking elements together at joining station 402 andthen wound onto outgoing spool 404.

FIG. 11 substitutes a supply spool 396 and separating station 398 forthe extrusion station 400 of FIG. 9.

FIG. 12 substitutes a package or bag making process 406, typically witha transverse direction zipper applicator (not shown), for the outgoingspool 404 of FIG. 10.

Thus the several aforementioned objects and advantages are mosteffectively attained. Although preferred embodiments of the inventionhave been disclosed and described in detail herein, it should beunderstood that this invention is in no sense limited thereby and itsscope is to be determined by that of the appended claims.

1. A zipper for a reclosable package, including: a first profileincluding a first interlocking element and a first flange; a secondprofile including a second interlocking element and a second flange; andthe first flange including a first row of apertures.
 2. The zipper ofclaim 1 wherein the second flange includes a second row of apertures. 3.The zipper of claim 1 wherein the first row of apertures is constructedand arranged to be engaged by a roll thereby resulting in the feeding ofthe zipper.
 4. The zipper of claim 1 wherein the apertures of the firstrow are formed by removing material from the first flange.
 5. The zipperof claim 1 wherein the apertures of the first row are formed byincisions in the first flange.
 6. The zipper of claim 1 wherein thefirst zipper profile further includes a third flange.
 7. The zipper ofclaim 1 wherein the first row of apertures is formed by a rotary punch.8. The zipper of claim 2 wherein the first and second rows of aperturesare formed by a rotary punch with two laterally adjacent sets ofprotrusions.
 9. The zipper of claim 1 wherein the zipper is constructedand arranged to be driven by adjacent first and second drive rolls whichengage the first row of apertures, wherein the movement of the first andsecond drive rolls is coordinated to adjust tension on the zipper. 10.The zipper of claim 1 wherein the zipper is formed by a step ofextrusion.
 11. The zipper of claim 10 wherein the first row of aperturesis formed by a rotary punching step after the step of extrusion.
 12. Thezipper of claim 1 wherein the first row of apertures is formed by arotary punching step after a step of supplying zipper material on aspool.
 13. The zipper of claim 1 wherein a step of package making isperformed after a step of forming the first row of apertures by a rotarypunch.
 14. A zipper for a reclosable package, including: a first profileincluding a first interlocking element and a first flange; a secondprofile including a second interlocking element and a second flange; andthe first flange including a rail protruding therefrom, the rail beingconstructed and arranged for engagement between opposed first and secondrolls for feeding the zipper.
 15. The zipper of claim 14 wherein therail has a T-shaped cross section.
 16. The zipper of claim 15 whereinthe T-shaped cross section is formed by a stem extending perpendicularlyfrom the flange and a head parallel to and separated from the flange.17. A zipper for a reclosable package, including: a first profileincluding a first interlocking element and a first flange; a secondprofile including a second interlocking element and a second flange; andthe first flange including a row of notches.
 18. The zipper of claim 17wherein the notches are parallel to each other.
 19. The zipper of claim18 wherein the notches are formed in a transverse direction with respectto a length of the zipper.
 20. The zipper of claim 19 wherein thenotches are constructed and arranged to be engaged by a gnurled driveroll for feeding the zipper.